There are two new entries to the list: the "Twilight" series by Stephenie Meyer and “My Sister’s Keeper” by Jodi Picoult.

Both Alice Walker’s “The Color Purple” and Robert Cormier’s “The Chocolate War” return after being dropped from the list in 2008.

For nearly 20 years, the library association's Office for Intellectual Freedom has collected reports on book challenges.

A challenge is defined as a formal, written complaint, filed with a library or school, requesting that materials be removed or restricted because of content or appropriateness. In 2009, the office received 460 reports on efforts to remove or restrict materials from school curricula and library bookshelves.

The office believes that a majority of challenges go unreported and that its statistics reflect only 20-25% of the ones that are actually filed.

“Even though not every book will be right for every reader, the ability to read, speak, think and express ourselves freely are core American values,” said Barbara Jones, director of the ALA’s Office for Intellectual Freedom. “Protecting one of our most fundamental rights – the freedom to read – means respecting each other’s differences and the right of all people to choose for themselves what they and their families read.”

The Top Ten Most Frequently Challenged Books of 2009 reflect a range of themes, and consist of the following titles:

While I don't approve of banning books, I wonder if the "unsuited to age group" isn't sometimes valid. We have a school system that insists children should arrive at kindergarten knowing the alphabet, and the algebra that used to be taught in high school is now taught in middle school. Are we also pushing texts like "Catcher in the Rye" and "Huckleberry Finn" to lower and lower levels? I know as an early reader, I usually read nonfiction in grade school because the fiction on my reading level had plot elements I either didn't understand or was uninterested in. (And at the same time, we are dumbing down the history texts until they contain no ideas worth thinking about!)